In recent years, the rapid development and popularization of smart phones to the mass have led to fierce competition among mobile phone manufactures and higher and higher requirements for the performance of display screens, and for this reason, it is extremely urgent for panel manufactures to optimize and improve existing display screens. As for the touch technique of display screens, common touch display panels on the present market are generally of an add-on type or an embedded type. Embedded-type touch display screens include in-cell touch display screens and on-cell touch display screens. Wherein, with the characteristics being light, thin, high in transmittance and simple in laminating process, the in-cell touch display screens stand out from the three types of touch display screens and are very popular with consumers, thereby having become the mainstream on the market. With the diversified development on the actual market, there have been requirements for in-cell touch display screens with many special resolutions, for instance, small-sized (smaller than 7″) display screens with special resolutions (18:9/19:9/20:9/21:9 and the like), display screens adopting the special Notch design, and embedded-type touch display screens with medium and large sizes (over 7″, vehicle-mounted, flat-panel and the like).
Under the limitations of touch sensitivity and anti-jamming capacity, the size of touch cells in the embedded-type touch display screens ranges from 3 mm*3 mm to 5 mm*5 mm. Under the condition where the size of the touch cells is known, the number of corresponding pixel cells in the horizontal direction of each touch cell and the number of corresponding pixel cells in the longitudinal direction of each touch cell are also basically determined. Furthermore, the number of the touch cells in the horizontal direction and the number of the touch cells in the longitudinal direction can also be determined according to the known resolution. Wherein, when the embedded-type touch screens have special resolutions, the number of the touch cells in the longitudinal direction may be out of proportion with the number of the pixel cells in the horizontal direction of each touch cell, and by the fact that the number of touch lines of the touch cells in each column is equal to the number of the touch cells in the longitudinal direction, the touch lines cannot be uniformly distributed to the touch cells in each column, consequentially, causing non-uniformity in linearity and sensitivity of the touch function and different display effects at the boundaries of the touch cells. For instance, when a touch display screen has a resolution of 1200 RGB*1920 and the number of the pixel cells corresponding to each touch cell is 40 RGB*40, the number of the touch cells in the horizontal direction of the touch display screen is 30, and the number of the touch cells in the longitudinal direction of the touch display screen is 48, that is to say, the number of the touch lines of the touch cells in each column is 48, while the number of the pixel cells in the horizontal direction of each touch cell is 40, and consequentially, the 48 touch lines cannot be uniformly distributed to the 40 pixel cells, in other words, the 48 touch lines cannot be uniformly distributed to the touch cells in each column.
As for small-sized embedded-type touch display screens encountering such problems, part of dually-arrayed touch lines can be separated into independent touch lines. Particularly, as shown in FIG. 1, when the number of the touch cells in the longitudinal direction is small and is in proportion with the number of the pixel cells in the horizontal direction of each touch cell (the number of the touch cells in the longitudinal direction is in proportion with the number of the pixel cells in the horizontal direction of each touch cell means that the number of the touch cells in the longitudinal direction is half, one third, the same, twice or the like of that of the pixel cells in the horizontal direction of each touch cell), dually-arrayed touch lines are used to control the touch cells. “Dually-arrayed” means that each pixel corresponds to two metal lines in parallel connection (namely two metal lines are used to control each touch cell), and the two metal lines are connected to a touch display integrated chip after being connected in parallel. By adoption of such line arrangement manner, the line impedance can be reduced, thus, avoiding impedance inconsistency between the near end and the far end of the touch display integrated chip. When the number of the touch cells in the longitudinal direction is out of proportion with the pixel cells in the horizontal direction of each touch cell, touch lines are dually and independently arrayed alternately to control the touch cells, wherein “independently-arrayed” means that each pixel corresponds to two independent metal lines, and in other words, two independent metal lines are used to control two touch cells and are respectively connected to a touch display integrated chip. For instance, when 48 touch lines are to be distributed to 40 pixel cells, 32 pixel cells of the 40 pixel cells can adopt dually-arrayed touch lines to control the corresponding touch cells, the other 8 pixel cells adopt independently-arrayed touch lines to control the corresponding touch cells, and in this way, the total number of the touch lines is 32+8*2, namely 48. By adoption of such line arrangement manner, in terms of RC evaluation, the independently-arrayed touch lines have to be disposed at the near end of the touch display integrated chip to minimize the impedance influence. However, in this case, the alternate arrangement manner of the touch lines may cause non-uniform RC loading, consequentially, affecting the display effect and the touch effect.
If the special Notch design is adopted for small-sized embedded-type touch display screens, the number of independently-arrayed touch lines needs to be increased, which will further worsen the impedance inconsistency and display non-uniformity.
If the small-sized embedded-type touch display screens are transformed into large-sized embedded-type touch display screens, the number of the touch cells in the longitudinal direction will be increased, and in this case, the number of the dually-arrayed touch lines cannot reach the number of the touch cells in the longitudinal direction. If the dually-arrayed touch lines are separated into independent touch lines, a large number of touch lines will be redundant, the number of channels of the touch display integrated chip will be increased by the redundant touch lines connected to the touch display integrated chip, and lines in the fan-out area are too dense, resulting in high risks in the manufacturing process.
In addition, as shown in FIG. 2, an array substrate of the traditional embedded-type touch display screens adopts the traditional 14-mask design. Particularly, the array substrate 100′ comprises a substrate 21′, metal blocks 22′, a buffer layer 23′, a poly-silicon layer 24′, a gate insulation layer 25′, a gate 26′, a first insulation interlayer 27′, a source/drain 28′, a planarization layer 29′, a second insulation interlayer 30′, touch lines 31′, a third insulation interlayer 32′, a transparent electrode layer 33′, a passivation layer 34′ and a pixel electrode layer 35′.
Wherein, a first metal layer M1 serves as a gate layer, a second metal layer M2 serves as a source/drain line layer, and a third metal layer M3 serves as a touch line layer. As the touch lines are arrayed in an independent layer and occupy two marks correspondingly formed on the touch lines 31′ and the third insulation interlayer 32′, and thus, the process is complex, and the material cost is high.